4.56pm: Leola Abraham from the Taupo District Council said the Department of Conservation put a helicopter up to look for people still on the mountain. She said DoC was still working to remove staff from Tongariro.

4.46pm: Gulf Harbour School Principal John Petrie said there were levels of apprehension after the eruption, but that the 20 Year 8 students felt safe.

"It's an experience I don't think our children will ever forget."

4.37pm: ONE News reporter Ruth Wynn-Williams said a huge column of ash is still coming out of the crater even though the mountain is no longer erupting.

4.30pm: Ash is expected to fall downwind of the mountain in the Waikato, Hawkes Bay and Bay of Plenty.

4.12pm: Area Commander Inspector Steve Bullock is reiterating a message for people to stay away from the volcano to avoid "unnecessary congestion" in the area.

4.01pm: State Highway 46, the road leading up to the mountain, is the only road affected by the eruption.

3.38pm: A group of 20 Year 8 students from Gulf Harbour School were also on Tongariro when it erupted. Deputy Principal Jane Cochrane said all the children were safe.

3.26pm: Air New Zealand says flights operating to some airports east of Mount Tongariro may be delayed or cancelled as a result of the eruption. Find if your flight has been delayed here.

3.13pm: A group of around 45 walkers with Adrift Outdoors are heading out of the area.

3.08pm: Tamatea Intermediate Principal Roy Sye said children were on a field trip eating lunch when the mountain "blew up".

"We had plans in place because we knew there was heightened risk."

3.04pm: Airways NZ said it will work with airlines to ensure flight paths are well above or around the ash and steam coming from the eruption, and said the cloud seems to be moving quite quickly.

3.01pm: Around 50 people are thought to be doing the Tongariro Crossing, and DoC spokeswoman Kim Turia said access roads to the mountain have been shut.

2.55pm: A group of school children on the Tongariro crossing are safe.

2.52pm: There have been no reports of injuries.

2.51pm: Sam Kennedy, who was filming in the area for Australian Geographic, said it was "pretty surreal". He said there was no noise or shaking of the ground before it erupted.

2.43pm: Senior Volcano Geophysicist Steve Sherburn said the eruption went on for about 5 mins. The ash went 2 or 3km above the crater before it drifted north-east.

"One of the key things is there was absolutely no warning of this the seismic stations we have monitoring Tongariro showed no activity before the eruption at all."

Sherburn said there are no volcanic patterns emerging because nature seems to be "throwing us curve balls at the moment".

2.34pm: Air New Zealand said on Twitter the eruption was not causing delays at the moment

This afternoon's eruption on Mt Tongariro caught scientists by surprise and has left them unsure what will happen next at the volcano.

Senior Volcano Geophysicist at GNS, Steve Sherburn, told ONE News there could be more activity in the next few weeks.

"I think for the next week or two weeks at least we're possibly in a situation where we may get additional activity - it's really hard to work out. This is the difficulty of dealing with a volcano like Tongariro."

The eruption lasted for about five minutes and sent an ash plume 3km into the sky.

No-one was injured and nearby residents have reported just a light dusting of ash on their properties. However, scientists are now struggling to predict what might happen next.

"One of the key things is there was absolutely no warning of this," Sherburn said. "The seismic stations we have monitoring Tongariro showed no activity before the eruption at all.

"Nature seems to be throwing us curve balls at the moment."

Witnesses say the eruption in the Te Maari Crater came 'out of the blue' with no ground shaking or increased activity at the vent.

It came from the the same crater as another blast in August which covered the local area in ash and forced the Department of Conservation to close off walking tracks.

However, within days the seismic activity around the volcano had dropped and the area was deemed safe again, making today's events all the more surprising.

"Because the eruption in August was the first for 100 years we don't know what a normal pattern of activity is," Sherburn said.

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"We do know in the 1880's and 1890's Tongariro did have a series of eruptions over a few months, and what we were thinking was the eruption earlier this year wasn't going to be followed by anything at all because everything was trending back to normal," Sherburn said.

Pressure has also been building beneath the crater lake of the nearby Mt Ruapehu and it has been suggested the heightened activity beneath both volcanoes could be linked.

However, Sherburn said he believes it is just a coincidence, "but I'd be glad for someone to prove me wrong".

--------

ffs it is completely obvious to amateurs that our volcanoes are connected

Re: WHAT IS HAPPENING AT WHITE ISLAND VOLCANO??? New Zealand/Kermadec & South Pacific QUAKE/VOLCANO WATCH

Yes, I'm amazed that they can say the various volcanoes are not connected. It must come from a reductionist point of view. The idea of breaking things down to their smallest components to get an understanding of the whole. Dumb.

I've been watching all the activity in NZ and it seems the whole place is waking up. The Christchurch quakes were the beginning, but the whole plate boundary area from top to bottom is squirming. Of course this is happening right around the Pacific and other places.

They're even wondering whether there might be some broader relationship between quakes and volcanoes. Talk about not putting two and two together.

It's also clear from them saying they didn't get any signs before this eruption and it's unusual, blah, blah, that they haven't really got a clue about it. About as useful as tits on a bullfrog.

Re: WHAT IS HAPPENING AT WHITE ISLAND VOLCANO??? New Zealand/Kermadec & South Pacific QUAKE/VOLCANO WATCH

Yes, I'm amazed that they can say the various volcanoes are not connected. It must come from a reductionist point of view. The idea of breaking things down to their smallest components to get an understanding of the whole. Dumb.

I've been watching all the activity in NZ and it seems the whole place is waking up. The Christchurch quakes were the beginning, but the whole plate boundary area from top to bottom is squirming. Of course this is happening right around the Pacific and other places.

They're even wondering whether there might be some broader relationship between quakes and volcanoes. Talk about not putting two and two together.

It's also clear from them saying they didn't get any signs before this eruption and it's unusual, blah, blah, that they haven't really got a clue about it. About as useful as tits on a bullfrog.

Quoting: Anonymous Coward 28089232

the idiots should read this thread, shouldnt they, lols

(instead they hate what i do here)

but seriously, you are correct in all you are saying, AC

M said days ago they should close the area, and she was right again

are the "experts" perhaps panicking and have no clue what to do atm?

btw i can see the ash on the coastal horizon, but cannot smell it yet

did you see the rotorua graphs i posted? likely a connection there too

local rotorua maori people who understand the big picture, and always have, say that the rotorua area is showing signs also, they said it months ago...

4.56pm: Leola Abraham from the Taupo District Council said the Department of Conservation put a helicopter up to look for people still on the mountain. She said DoC was still working to remove staff from Tongariro.

4.46pm: Gulf Harbour School Principal John Petrie said there were levels of apprehension after the eruption, but that the 20 Year 8 students felt safe.

"It's an experience I don't think our children will ever forget."

4.37pm: ONE News reporter Ruth Wynn-Williams said a huge column of ash is still coming out of the crater even though the mountain is no longer erupting.

4.30pm: Ash is expected to fall downwind of the mountain in the Waikato, Hawkes Bay and Bay of Plenty.

4.12pm: Area Commander Inspector Steve Bullock is reiterating a message for people to stay away from the volcano to avoid "unnecessary congestion" in the area.

4.01pm: State Highway 46, the road leading up to the mountain, is the only road affected by the eruption.

3.38pm: A group of 20 Year 8 students from Gulf Harbour School were also on Tongariro when it erupted. Deputy Principal Jane Cochrane said all the children were safe.

3.26pm: Air New Zealand says flights operating to some airports east of Mount Tongariro may be delayed or cancelled as a result of the eruption. Find if your flight has been delayed here.

3.13pm: A group of around 45 walkers with Adrift Outdoors are heading out of the area.

3.08pm: Tamatea Intermediate Principal Roy Sye said children were on a field trip eating lunch when the mountain "blew up".

"We had plans in place because we knew there was heightened risk."

3.04pm: Airways NZ said it will work with airlines to ensure flight paths are well above or around the ash and steam coming from the eruption, and said the cloud seems to be moving quite quickly.

3.01pm: Around 50 people are thought to be doing the Tongariro Crossing, and DoC spokeswoman Kim Turia said access roads to the mountain have been shut.

2.55pm: A group of school children on the Tongariro crossing are safe.

2.52pm: There have been no reports of injuries.

2.51pm: Sam Kennedy, who was filming in the area for Australian Geographic, said it was "pretty surreal". He said there was no noise or shaking of the ground before it erupted.

2.43pm: Senior Volcano Geophysicist Steve Sherburn said the eruption went on for about 5 mins. The ash went 2 or 3km above the crater before it drifted north-east.

"One of the key things is there was absolutely no warning of this the seismic stations we have monitoring Tongariro showed no activity before the eruption at all."

Sherburn said there are no volcanic patterns emerging because nature seems to be "throwing us curve balls at the moment".

2.34pm: Air New Zealand said on Twitter the eruption was not causing delays at the moment

yes, i wonder if other kiwis have thought of plastic and duct tape to seal their homes in ash affected areas

take note of nines' good advice here, kiwis

i can see the smoke on my coastal horizon, but it isnt noticeable in the air here, because the wind is not bringing it here yet, and i cant smell it yet

love you heaps, sis xxx

Quoting: Tauranga

Luv you too sis. Good you can't yet smell it. Someone once told me that when you breathe it in and it contacts the moisture in your lungs, it really messes you up. Like making cement in your lungs. Hope it was an exaggeration, but don't take any chance.

yes, i wonder if other kiwis have thought of plastic and duct tape to seal their homes in ash affected areas

take note of nines' good advice here, kiwis

i can see the smoke on my coastal horizon, but it isnt noticeable in the air here, because the wind is not bringing it here yet, and i cant smell it yet

love you heaps, sis xxx

Quoting: Tauranga

Luv you too sis. Good you can't yet smell it. Someone once told me that when you breathe it in and it contacts the moisture in your lungs, it really messes you up. Like making cement in your lungs. Hope it was an exaggeration, but don't take any chance.

Quoting: Nine's

that will be why they are telling us all to stay indoors, just in case i guess

"We didn't hear anything but could suddenly see an ominous dark grey cloud of ash drifting towards us" said Fournier.

The eruption was also seen by trampers walking on the Tongariro Crossing. Ash erupted during the first few minutes reached 3 km to 4 km height and was clearly seen from Taupo.

There are no reports of injury.

Further eruptions possible

GNS also said that this afternoon's eruption occurred without any measured precursory changes, highlighting the unpredictable nature of volcanoes.

Senior Volcano Geophysicist Steve Sherburn told ONE News there no warning signs before the eruption.

"One of the key things is there was absolutely no warning of this the seismic stations we have monitoring Tongariro showed no activity before the eruption at all."

Sherburn said there are no volcanic patterns emerging because nature seems to be "throwing us curve balls at the moment".

GNS also said that any further eruptions are not expected to escalate in size.

"We cannot say what will happen next at Tongariro but the scenario considered most likely, based on the August 2012 eruption and the description of late 1890's eruptions, is that we could expect another eruption of similar size at any time during the next few weeks," scientists said.

Light dusting of ash

Locals are reporting a light dusting of ash on their properties, following the eruption of a crater on Mount Tongariro this afternoon.

"The families in the south east corner say they have got a very light dusting of ash," local resident Bubs Smith told ONE News.

"I suppose Tongariro has had a big cough, it's got the ash cloud circling around, but on the north east side there's still a bit of ash to come down," he said earlier.

A light dusting of ash fell across part of State Highway 46 and northeast towards Turangi but no more ash has been reported this afternoon as the gas and steam cloud drifts towards the south east.

Ash is being collected this afternoon and will be analysed at Massey University to assess potential human and animal health effects, GNS reported.

At this stage, Wellington Airport has only cancelled two afternoon flights between Taupo and Wellington.

Airways NZ said they are working with the airlines to ensure their flight paths are well above or around the cloud of ash and steam coming from the eruption.

Trampers safe

Taupo police report that there are no road closures in place at this stage, but advises people against sight-seeing trips to the area.

"We don't want unnecessary congestion to contend with, and want to ensure the road network remains free-flowing just in case there is any further volcanic activity," said Inspector Steve Bullock.

Meanwhile, a bus company has confirmed that 90 children and eight adults who were visiting the mountain are now safe.

Tamatea Intermediate Principal Roy Sye said the children were on a field trip eating lunch when the mountain "blew up".

"We had plans in place because we knew there was heightened risk," he told ONE News.

Similarly, Greg Hooper from Tongariro Holiday Park told ONE News that he saw a haze in the distance, and lots of cloud cover.

Hooper said he is waiting for a group of 40 people to return from the mountain, but he had received confirmation from members of the group that they are all safe.

According to GNS, Tongariro is a complex of multiple volcanic cones constructed over a period of 275,000 years.

The active vents include Te Maari, Emerald, North Crater and Red Crater.

There have been five reported eruptions from the Te Maari craters between 1855 and 1897 but they have been dormant until 2012.

An outing turned into terror for a group of school children visiting Mount Tongariro today.

Ninety children and eight adults from Napier's Tamatea Intermediate were eating their lunch when the Te Maari crater erupted about 1.25pm.

The "shaken" children, rushed back to the school bus which was waiting for them at the end of the track.

Amateur video shows the children running down the track, some screaming, as an ominous black cloud of ash rises behind them.

"It was a very exciting day, not quite the day we had planned," said Principal Roy Sye. "They are studying volcanoes, so they got a first-hand look at when nature goes unannounced."

The school's outing was their second trip to the volatile region in the last two weeks.

"We looked at the DOC warnings and advisories, and we do make sure we ring and check on the day for any heightened level of risk," Sye said.

Twenty students and eleven staff from Auckland's Gulf Harbour School also made their way safely back down the mountain.

Sam Kennedy was one of 50 trampers on the Tongariro Alpine Crossing when the eruption occurred.

"It was completely silent. It was just really eerie and surreal," he said.

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Earlier, Greg Hooper from Tongariro Holiday Park told ONE News that he saw a haze in the distance, and lots of cloud cover.

Hooper said he knew of 40 Holiday Park guests who were visiting the mountain, but received confirmation soon after the eruption from members of the group that they were all safe and sound.

Unexpected eruption

Scientists cannot rule out that today's eruption is linked to recent volcanic activity on Mount Ruapehu.

"We were not expecting this. The stuff at Ruapehu think there's no link, but maybe there is, maybe we don't understand it well enough," said volcanologist Steve Sherburn.

"We may see several more rumbles over the next few days but because nothing told us this was coming, it was very hard to look forward and say we've seen this, therefore there must be another eruption, so I guess we're like everybody - on the edge of our seats," he said.

Meanwhile, the Civil Aviation Authority is monitoring the spread of the ash cloud.

"The eruption has extended to about 15,000 feet and the plume will spread out over the central plateau over the next twelve hours or so and then it will dissipate over the next few days," said Civil Aviation Authority's Peter Lechner.

Civil defence has issued a warning that an ash cloud could be looming over the central North Island from Waikato to the Hawke's Bay for several days.

This afternoon's eruption on Mt Tongariro caught scientists by surprise and has left them unsure what will happen next at the volcano.

Senior Volcano Geophysicist at GNS, Steve Sherburn, told ONE News there could be more activity in the next few weeks.

"I think for the next week or two weeks at least we're possibly in a situation where we may get additional activity - it's really hard to work out. This is the difficulty of dealing with a volcano like Tongariro."

The eruption lasted for about five minutes and sent an ash plume 3km into the sky.

No-one was injured and nearby residents have reported just a light dusting of ash on their properties. However, scientists are now struggling to predict what might happen next.

"One of the key things is there was absolutely no warning of this," Sherburn said. "The seismic stations we have monitoring Tongariro showed no activity before the eruption at all.

"Nature seems to be throwing us curve balls at the moment."

Witnesses say the eruption in the Te Maari Crater came 'out of the blue' with no ground shaking or increased activity at the vent.

It came from the the same crater as another blast in August which covered the local area in ash and forced the Department of Conservation to close off walking tracks.

However, within days the seismic activity around the volcano had dropped and the area was deemed safe again, making today's events all the more surprising.

"Because the eruption in August was the first for 100 years we don't know what a normal pattern of activity is," Sherburn said.

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"We do know in the 1880's and 1890's Tongariro did have a series of eruptions over a few months, and what we were thinking was the eruption earlier this year wasn't going to be followed by anything at all because everything was trending back to normal," Sherburn said.

Pressure has also been building beneath the crater lake of the nearby Mt Ruapehu and it has been suggested the heightened activity beneath both volcanoes could be linked.

However, Sherburn said he believes it is just a coincidence, "but I'd be glad for someone to prove me wrong".

--------

ffs it is completely obvious to amateurs that our volcanoes are connected

what bloody "proof' do they need!!!

unbelievable head in the sand attitude going on here

Quoting: Tauranga

That comment I put in bold in athe article is such utter bullshit...we have been commenting that the steaming at the vent had intensified significantly in recent days ....and there have been lots of small lumpy signals on the drums as well!

I think we will see activity everywhere in NZ eventually. And I think it will be together during the same time period, with lots of small eruptions at multiple locations over the coming years ( maybe months ). We will see.

Interested observer of all things interesting!

Please note : Where appropriate for posted images/ graphs I acknowledge the New Zealand GeoNet project and its sponsors EQC, GNS Science and LINZ, for providing data/images used in my study and analyses of Volcanic and Earthquake information in New Zealand.

Re: WHAT IS HAPPENING AT WHITE ISLAND VOLCANO??? New Zealand/Kermadec & South Pacific QUAKE/VOLCANO WATCH

Yes, I'm amazed that they can say the various volcanoes are not connected. It must come from a reductionist point of view. The idea of breaking things down to their smallest components to get an understanding of the whole. Dumb.

I've been watching all the activity in NZ and it seems the whole place is waking up. The Christchurch quakes were the beginning, but the whole plate boundary area from top to bottom is squirming. Of course this is happening right around the Pacific and other places.

They're even wondering whether there might be some broader relationship between quakes and volcanoes. Talk about not putting two and two together.

It's also clear from them saying they didn't get any signs before this eruption and it's unusual, blah, blah, that they haven't really got a clue about it. About as useful as tits on a bullfrog.

Quoting: Anonymous Coward 28089232

the idiots should read this thread, shouldnt they, lols

(instead they hate what i do here)

but seriously, you are correct in all you are saying, AC

M said days ago they should close the area, and she was right again

are the "experts" perhaps panicking and have no clue what to do atm?

btw i can see the ash on the coastal horizon, but cannot smell it yet

did you see the rotorua graphs i posted? likely a connection there too

local rotorua maori people who understand the big picture, and always have, say that the rotorua area is showing signs also, they said it months ago...

Quoting: Tauranga

Yeah thanks, T. I'm not too familiar with the graphs, but I've had a look. The Maori are more likely to have the pulse of the place than the 'experts'.

Also, I guess the 'experts' have to be careful because of the tourist trade and so on. None of them want to be accused of being alarmist if nothing much comes of it.

It's really up to people themselves to take notice since it might save their lives if they're just a bit prepared. The ones (majority) who wait for the authorities to tell them what to do might be left twisting in the wind.

I've got a bad feeling it's only beginning. Best of luck and good management to all there.

Re: WHAT IS HAPPENING AT WHITE ISLAND VOLCANO??? New Zealand/Kermadec & South Pacific QUAKE/VOLCANO WATCH

Yes, I'm amazed that they can say the various volcanoes are not connected. It must come from a reductionist point of view. The idea of breaking things down to their smallest components to get an understanding of the whole. Dumb.

I've been watching all the activity in NZ and it seems the whole place is waking up. The Christchurch quakes were the beginning, but the whole plate boundary area from top to bottom is squirming. Of course this is happening right around the Pacific and other places.

They're even wondering whether there might be some broader relationship between quakes and volcanoes. Talk about not putting two and two together.

It's also clear from them saying they didn't get any signs before this eruption and it's unusual, blah, blah, that they haven't really got a clue about it. About as useful as tits on a bullfrog.

Quoting: Anonymous Coward 28089232

the idiots should read this thread, shouldnt they, lols

(instead they hate what i do here)

but seriously, you are correct in all you are saying, AC

M said days ago they should close the area, and she was right again

are the "experts" perhaps panicking and have no clue what to do atm?

btw i can see the ash on the coastal horizon, but cannot smell it yet

did you see the rotorua graphs i posted? likely a connection there too

local rotorua maori people who understand the big picture, and always have, say that the rotorua area is showing signs also, they said it months ago...

Quoting: Tauranga

Yeah thanks, T. I'm not too familiar with the graphs, but I've had a look. The Maori are more likely to have the pulse of the place than the 'experts'.

Also, I guess the 'experts' have to be careful because of the tourist trade and so on. None of them want to be accused of being alarmist if nothing much comes of it.

It's really up to people themselves to take notice since it might save their lives if they're just a bit prepared. The ones (majority) who wait for the authorities to tell them what to do might be left twisting in the wind.

I've got a bad feeling it's only beginning. Best of luck and good management to all there.

Quoting: Anonymous Coward 28089232

thank you friend xx

yes it is just beginning

the trouble is that people trust the 'experts' to warn them, same old story, i guess...

This afternoon's eruption on Mt Tongariro caught scientists by surprise and has left them unsure what will happen next at the volcano.

Senior Volcano Geophysicist at GNS, Steve Sherburn, told ONE News there could be more activity in the next few weeks.

"I think for the next week or two weeks at least we're possibly in a situation where we may get additional activity - it's really hard to work out. This is the difficulty of dealing with a volcano like Tongariro."

The eruption lasted for about five minutes and sent an ash plume 3km into the sky.

No-one was injured and nearby residents have reported just a light dusting of ash on their properties. However, scientists are now struggling to predict what might happen next.

"One of the key things is there was absolutely no warning of this," Sherburn said. "The seismic stations we have monitoring Tongariro showed no activity before the eruption at all.

"Nature seems to be throwing us curve balls at the moment."

Witnesses say the eruption in the Te Maari Crater came 'out of the blue' with no ground shaking or increased activity at the vent.

It came from the the same crater as another blast in August which covered the local area in ash and forced the Department of Conservation to close off walking tracks.

However, within days the seismic activity around the volcano had dropped and the area was deemed safe again, making today's events all the more surprising.

"Because the eruption in August was the first for 100 years we don't know what a normal pattern of activity is," Sherburn said.

Advertisement

"We do know in the 1880's and 1890's Tongariro did have a series of eruptions over a few months, and what we were thinking was the eruption earlier this year wasn't going to be followed by anything at all because everything was trending back to normal," Sherburn said.

Pressure has also been building beneath the crater lake of the nearby Mt Ruapehu and it has been suggested the heightened activity beneath both volcanoes could be linked.

However, Sherburn said he believes it is just a coincidence, "but I'd be glad for someone to prove me wrong".

--------

ffs it is completely obvious to amateurs that our volcanoes are connected

what bloody "proof' do they need!!!

unbelievable head in the sand attitude going on here

Quoting: Tauranga

That comment I put in bold in athe article is such utter bullshit...we have been commenting that the steaming at the vent had intensified significantly in recent days ....and there have been lots of small lumpy signals on the drums as well!

I think we will see activity everywhere in NZ eventually. And I think it will be together during the same time period, with lots of small eruptions at multiple locations over the coming years ( maybe months ). We will see.

Quoting: taniatarn

hiya tarn

i was gonna ring you..

utter bullshit is correct

they are so busy being 'experts' that peoples safety doesnt seem to matter

you, M, and i have been trying to warn that something is going on there!

this is disgusting, how dare they have allowed children to go up there when it was so damn OBVIOUS to us amateurs that it was unsafe up there

Police say they are working alongside the Department of Conservation following an ash and gas eruption at the Te Maari crater on Mt Tongariro this afternoon.

Inspector Steve Bullock, area commander for Taupo police, says while there are no road closures currently in place, he would "discourage" sightseers from travelling to the area.

"We don't want unnecessary congestion to contend with, and want to ensure the road network remains free-flowing just in case there is any further volcanic activity."

There have been no reports of injury and there are no search and rescue requirements at this stage.

The mountain silently blasted ash and gas 2km into the sky from Te Maari crater, on the western side of the mountain, about 1.25pm today, authorities said.

Police and Department of Conservation (DoC) staff have closed the Tongariro Alpine Crossing at Ketetahi and Mangatepopo roads, where the track starts and finishes.

DoC community relations manager Kim Alexander-Turia said about 50 people were thought to be on the crossing at the time of the eruption.

All were thought to be safe and were making their way off the track in their own time.

"The difference between this eruption and the last eruption is there's no volcanic rocks coming out, so we're just letting people quickly and safely come off in their own time, calmly.

"We're just trying to get them off the mountain as soon as possible."

Ms Alexander-Turia said a flyover later today would confirm whether everyone had made it off the mountain safely.

The eruption prompted an aviation alert increase from yellow to red.

Sara Page from GeoNet said the alert was upgraded because the eruption was underway with "significant ash in the atmosphere".

Air New Zealand said there may be delays or cancellations on domestic services to airports east of the mountain.

But the airline said it would adjust flight routes and altitudes if required ensuring aircraft remain clear of any ash.

GNS Science duty volcanologist Nico Fournier told APNZ there was one eruption, "essentially one explosion, and it was not sustained".

Dr Fournier said the eruption was not very loud and was smaller than an earlier eruption in August.

Last week GNS Science increased the likelihood of neighbouring volcano Mt Ruapehu erupting, following increased activity on the mountain.

Dr Fournier said there was "quite a bit of gas" but it was quietening down.

The next step was to work with DoC and authorities to make sure people in the area were safe.

Adrift NZ, which runs tours of the Tongariro Alpine Crossing, had about 50 people on the mountain today.

Operator Stewart Barclay, who chairs a group of 30 users of Mt Tongariro, was heading to Mt Tongariro to help his guides and their groups off the mountain.

"I'm just going to make sure everyone is safe ... from my guide's perspective and from what I've heard, it seems minor."

Mr Barclay understood the eruption had launched no projectiles into the air.

"There was a minor amount of panic and everyone is safe now, there were no injuries."

Staff and students from Tamatea Intermediate in Hawkes Bay are safe and well after being on the Tongariro Track at the base of the volcano during a volcanic eruption this afternoon.

About 100 staff and students were about two hours into the track when the eruption occurred.

A school spokesman said the staff and students were okay and were coming down the mountain.

The Ministry of Civil Defence and Emergency Management issued a national advisory just under an hour after the eruption.

It said "minor volcanic activity" at Tongariro's Te Maari craters could be hazardous in the immediate vicinity.

Light volcanic ashfall was anticipated downwind of Tongariro and could fall in Waikato, Hawkes Bay, Gisborne and Bay of Plenty.

People living in or near the affected areas were advised to stay indoors and close windows and doors if ash fell. People who were outdoors should seek shelter.

For more on what to do during an ash fall, see here.

Civil Defence said ash could be a health hazard, especially for people suffering breathing difficulties.

People affected by ashfall should wear a dust mask cover their nose and mouth and protect their eyes.

A woman who lives near the mountain said sulphur-smelling ash had been raining down on her home.

Robyn Bennett, who lives 6km from the mountain, said she could see the plume of ash rising into the sky.

"It's sitting under some cloud and that's why it's pushing down onto us," she said.

"It smells worse than rotten eggs."

Ms Bennett didn't think she and her husband would need to leave their home, "not unless she starts spewing out a whole lot of red rocks", but they were waiting to hear from Civil Defence or DoC.

James Perry, who works at the Lake Taupo Hole in One attraction on the resort town's lakefront, had a clear view of the mountains of the central plateau and saw the ash as soon as the eruption occurred.

"It basically went straight up and did the mushroom cloud and then the wind's just spread it from there," he said.

Hole in One owner Tiffany Battell said the smell of sulphur was obvious yesterday and she had wondered then whether it was a precursor to another eruption.

Rhys Harnett of Auckland had stopped on the lakefront to eat his lunch at about 1.30pm when he saw black smoke rising silently from the crater of Mt Tongariro, which he said plumed out above the clouds. He took a photo on his cellphone and rang his home in Auckland to relate what he had seen.

"I had a feeling it was not an eruption but letting off steam."

WeatherWatch head weather analyst Philip Duncan said with only light winds in the region, much of the ash was expected to fall locally.

Lighter ash could travel greater distances and the plume may drift anywhere anywhere from Taupo to Hawkes Bay.

Ash was expected to fall on the Desert Road but was likely to be pushed away from the main air route, to the west of the mountain.

Tongariro, in the centre of the North Island, erupted in August for the first time in 115 years, sending ash as far east as Napier.

According to GeoNet, Tongariro is a complex of multiple volcanic cones constructed over a period of 275,000 years.

The mountain's active vents include Te Maari, Emerald, North Crater and Red Crater.

video:Staff at Tamatea Intermediate School capture the first moments of the eruption

A teacher who was on Mt Tongariro with a group of 90 students has captured the ‘‘absolutely spectacular’’ eruption of the volcano on video.

GNS Science confirmed the eruption, at the Te Maari crater, happened shortly after 1.20pm. It is the second eruption on the mountain this year; an eruption on August 6 was the first on Tongariro for more than 100 years.

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Tamatea Intermediate teacher Lomi Schaumkel said they were near the Katetahi hot springs when eruption began.

‘‘We were right up there next to it. It was just amazing. It was pretty scary from where we were and it just looked absolutely spectacular, the ash that came out. It really did look like one of those atom bomb explosions, and it made a rumbling sound.’’

There were 90 students, six parents and four teachers in the group.

‘‘Some panicked, some didn’t. Everyone came down safely and it was great’’.

The group were about 1 km away from the eruption, Schaumkel said.

''We saw all these tourists running away from it. We didn't stick around long.''

A further 20 Year 8 pupils from Gulf Harbour School in Whangaparoa were making their way off the track with parents and guides after being just 750m from where the crater erupted.

Two bus drivers from Nimon and Sons, who took the Napier children to the mountain, had reported back to their base that they could see an ash plume 2km high, a spokesman said.

The probability of a large aftershock somewhere in the central Canterbury earthquake zone continues to drop as a result of lower seismic activity in recent months.

In GNS Science's updated calculations released today, the probability of a magnitude 5.0 to 5.4 shake in the next 12 months is 69 per cent, compared with 82 per cent in January.

Over the same period there is a 29 per cent chance of a magnitude 5.5 to 5.9 quake in the aftershock zone, which runs from the foothills in the west to Pegasus Bay in the east and from Rangiora in the north to Tai Tapu in the south.That has fallen from a 39 per cent probability in January.

The chance of a magnitude 6.0 to 6.4 aftershock is now 9 per cent, down from 13 per cent in January, while there is only a 2 per cent probability of a magnitude 6.5 to 6.9 event in the next year, down from 4 per cent at the start of the year.

GNS Science says the probability of a magnitude 7 or higher quake in the next year remains unchanged at 1 per cent.

The Lake Taupo cycle challenge began at midday with the enduro riders starting the first of their eight laps of the lake.

Within minutes of the eruption, organiser Hayden Dickason had more marshals out on the course to warn the cyclists of the volcanic activity and to check which direction the wind was blowing.

He says he needs to keep a watch on any ash, because he does not want riders breathing it in.

Mr Dickason told NBR ONLINE he has a contingency plan in place.

The majority of the 8500 entrants will ride just one lap of the lake on Saturday.

“For event day itself, in the unlikely event something big happens we’ve definitely got contingency plans in place to alert people straight away.

"Obviously, we also work with civil defence and police. Should the untoward happen when we need to hold the ride, we’ve got destinations around the lake where people can gather.”

Mr Dickason says he saw the eruption from his office window and because the mountain was covered in cloud at that stage,it just looked like another cloud peeping out the top.

Civil defence has issued a volcanic activity warning and says light volcanic ash fall can be anticipated downwind of Tongariro and may affect Waikato, Hawke’s Bay, Gisborne and Bay of Plenty.

Civil defence says more information will come later in the day from the Department of Conservation and other local authorities with up on the mountain.

Air New Zealand says it is working closely with the Civil Aviation Authority, the MetService and other authorities to keep up to date with ash movement and forecasts.

General manager airline operations and safety, Captain David Morgan, who is also chief pilot, says they are working with the relevant authorities to safely make adjustments to flight routes to ensure aircraft remain clear of any ash.

Passengers are advised to check the Air NZ website for flight arrivals and departures information.